ML20214T456

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Forwards Addl Info on Overfill of once-through Steam Generator & Main Steam Line Which Occurred During 851226 Transient.Nde Tests & Ultrasonic & Magnetic Particle Performed on Piping & Indicate No Damage Due to Overfill
ML20214T456
Person / Time
Site: Rancho Seco
Issue date: 06/02/1987
From: Andognini G
SACRAMENTO MUNICIPAL UTILITY DISTRICT
To: Miraglia F
Office of Nuclear Reactor Regulation
References
GCA-87-092, GCA-87-92, NUDOCS 8706100274
Download: ML20214T456 (2)


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SACRAMENTO MUNICIPAL UTILITY DISTRICT O P. O. Box 15830 Sacramento CA 95852-1830,(916) 452-3211 AN ELECTRIC SYSTEM SERVING THE HEART OF CALIFORNIA GCA 87-092 JUN 0 21997 U. S. Nuclear Regulatory Commission Attn: Frank J. Miraglia, Jr.

Associate Director for Projects Philips Building 7920 Norfolk Avenue Bethesda, MD 20014 DOCKET 50-312 RANCHO SECO NUCLEAR GENERATING STATION UNIT 1 LICENSE NO. DPR-54 OTSG OVERFILL AND FLOODING OF THE MAIN STEAM LINE The staff had requested additional information on the overfill of the OTSG and Main Steam line which occurred during the December 26, 1985 transient.

Attached are the responses to the questions asked by the NRC reviewer concerning the impact on the OTSG, Main Steam line and Main Steam Bypass line as a result of the overfill.

If there are any questions, please contact John Atwell, extension 3906, at Rancho Seco.

Sincerely, dh)ms G. Carl Andognini Chief Executive Officer, Nuclear Attachment cc w/atch:

G. Kalman, NRC, Bethesda (2) l A. D'Angelo, NRC, Rancho Seco l E Dr D'70602 -

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- "> - ATTACHMENT Question: Provide an evaluation and verification that the design limits for the supports of the steam generator, the "A" main steam line and the "A" main steam bypass line have rot been exceeded due to overflow and the injection of the 13000 gallons of water.

Response: An evaluation of the OTSG and piping supports has been performed.

Review of the original design calculations for the OTSG support skirt shows that the dead weight of a flooded OTSG vessel (2,000,000 lbs) was considered and met the ASME code allowables.

The piping supports were evaluated using walkdowns of the Main Steam and Bypass lines to evaluate the effects, if any, on the supports. These walkdowns indicated that there had been no adverse impact on the piping supports.

Therefore, impact on the supports of the OTSG, Main Steam and Bypass lines has been evaluated by the District and found to be within design allowables or to have caused no detrimental effect to the supports.

Question: Provide the results of the detailed examination of the welds and piping of the bypass line currently being performed.

Response: Non-destructive examination (NDE) tests, ultrasonic and magnetic particle, have been performed on the piping and indicate no damage occurred as a result of the stress induced by the overfill.

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